Grigori Perelman had the answer the mathematical world had sought for almost a century.
In 1904, the French mathematician Henri Poincaré posed a puzzle about the shape of the universe that no expert managed to solve. Perelman solved it in 2002 and published the proof online, without asking for anything in return. He built on the previous work of Richard Hamilton, and that detail would ultimately prove key to his decision.
In 2006, in Madrid, he was offered the Fields Medal, the most important recognition for a mathematician. He did not go to receive it. In 2010, the Clay Mathematics Institute put a check for one million dollars in his hand. He did not accept that either. He said he did not want to be displayed like a zoo animal. Today he lives in a small apartment in Saint Petersburg, with his mother and sister, far from universities and cameras.
